Computers and electronic equipment of all types rely on integrated circuits. An integrated circuit, also known as IC or microcircuit, is a miniaturized electronic circuit, which is made of mainly semiconductive devices and passive compents that have been manufactured in the surface of a thin substrate of semiconductor material. Semiconductor devices include a plurality of circuits connected to form a more complex integrated circuit and often contain millions of transistors and other circuit elements fabricated on a single silicon crystal semiconductor device. For the device to be functional, a complex network of signal paths will normally be routed to connect the circuit elements distributed on the surface of the device. Efficient routing of these signals across the device can become more difficult as the complexity and number of the integrated circuits is increased. Thus, the formation of multi-level or multi-layered interconnection schemes such as, for example, dual damascene wiring structures, have become more popular due to their efficacy in providing high speed signal routing patterns between large numbers of transistors on a complex semiconductor chip.
When fabricating integrated circuit wiring with a multi-layered scheme, an insulating or dielectric material such as silicon oxide or other low dielectric (low-k) constant insulators are normally patterned with several thousand openings to create conductive line openings and/or via openings using photo patterning and plasma etching techniques such as photolithography with subsequent etching by plasma processes. These via openings are typically filled with a conductive metal material such as aluminum, copper, etc., to interconnect the active and/or passive elements of the integrated circuits. The semiconductor device is then polished to level its surface.
In some instances, a continuous cap layer is then deposited over the planarized surface featuring the dielectric material and conductive metal material. Next, a dielectric material is deposited over the continuous cap layer, via and conductive line openings are created within the dielectric layer as before, another conductive metal material is deposited within the openings and another continuous cap layer is deposited thereon. The process is repeated to fabricate a multi-layer interconnect wiring system. This multi-layer interconnect wiring system is fabricated using a variety of apparatuses including, for example, an apparatus for film deposition, photolithography, reactive ion etching, copper plating, chemical-mechanical polishing, etc. The process to fabricate the multi-layer interconnect system resulting from these steps is called a dual damascene integration scheme.
This dual damascene integration scheme is cumbersome and constitutes a significant part of the manufacturing cost of advanced semiconductor chips having many layers. Many sacrificial films are required to pattern and protect the fragile interlayer dielectric films from damage during plasma and wet processing. These sacrificial patterning and protective films have to be removed after patterning and copper plating, which is time consuming and wasteful. To circumvent these drawbacks, materials that incorporate the properties of both the photoresist and the dielectric materials are highly desirable. This combination material, called photo-patternable low-k dielectric, acts as a photoresist during the lithographic patterning process. It is subsequently converted into a low-k material during post patterning cure. The post patterning cure of the photo-patternable low-k dielectric material removes unwanted organic components and/or sacrificial pore generator (porogens) and forms a more mechanically robust molecular network through crosslinking. Photo-patternable low-k dielectric material is disclosed in U.S. Pat. Nos. 7,041,748, 7,056,840, and 6,087,064, all of which are incorporated herein by reference in their entirety. These types of photo-patternable low-k dielectric material eliminates the need for the many sacrificial materials and the corresponding plasma etching. It also dramatically reduces the steps and complexity involved in the dual damascene fabrication of metal/dielectric interconnects resulting in a speedy and cost-effective solution for manufacturing advanced ICs.